NTSB Factual Report

HISTORY OF FLIGHT

On August 7, 2011, about 1350 eastern daylight time, a Maule M-7-235, N747GL, was substantially damaged when it impacted the ground during approach to Warrenton Air Park (7VG0), Warrenton, Virginia. The certificated commercial pilot and passenger were fatally injured. The airplane came to rest upright and a post-impact fire ensued, consuming the airplane except for a portion of the left wing and the two amphibious floats. The airplane was registered to an individual and the personal flight was operated under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed and an instrument rules flight plan had been filed. The flight originated from Potomac Airfield (VKX), Friendly, Maryland, at 1315.

The owner of the airplane stated that the accident pilot called him about 1315 and informed him that he was going to fly the float plane to 7VG0. The owner further stated that he observed the airplane enter the downwind leg of the traffic pattern for runway 4 at 7VG0, and while turning from the base leg to the final leg of the approach, the airplane banked to the left. The airplane appeared to continue to bank to about 75 degrees, at which point the nose pitched down to an almost vertical attitude. The airplane descended and impacted the ground in an open field prior to the runway threshold and "exploded."

Another witness reported that she observed the airplane flying over the north end of the runway and turn onto the downwind leg of the traffic pattern. When she looked up again, the airplane was in a bank and then entered a dive. She observed the airplane impact the ground and "explode."

PERSONNEL INFORMATION

The pilot, age 42, held a commercial pilot certificate with ratings for airplane single-engine land, multiengine land, single-engine sea, and instrument airplane. His most recent application for a Federal Aviation Administration (FAA) second-class medical certificate was issued on August 10, 2010. A review of the pilot's logbook revealed approximately 1,300 total hours of flight experience, which included 1,066 total hours in airplane single-engine; however, an accurate flight time total in the make and model of aircraft could not be determined.

AIRCRAFT INFORMATION

The four-seat, high-wing, amphibious airplane, was manufactured in 1994 and was issued an FAA airworthiness certificate on March 4, 1994. It was equipped with a Lycoming O-540-J1A5D, 235-horsepower engine and a three-bladed McCauley propeller. The airplane's most recent annual inspection could not be determined since the owner was not able to locate the maintenance logbooks after the accident.

AIRPORT INFORMATION

The airport was privately-owned and at the time of the accident did not have an operating control tower. The airport was equipped with two runways, designated 04/22 and 15/33. The turf runways were reported in good condition. Runway 04/22 was 2,215 feet long by 70 feet wide runway and runway 15/33 was 2,000 feet long by 70 feet wide. Runway 04/22 had the following note associated with its use: "Narrows to 70 ft usbl at bridge over stream mowed to 240 feet wide." Runway 15/33 had several notes associated with its use and they are as follows: "Width mowed & mkd by orange cones; turf are aprxly 250 feet wide” and “landing only rwy 33; no takeoffs rwy 33 no takeoffs/landing rwy 15." The airport was 442 feet above mean sea level.

METEOROLOGICALINFORMATION

The 1355 recorded weather observation at Warrenton-Fauquier Airport (HWY) Warrenton, Virginia, located about 10 miles southeast of the accident location, included wind from 220 degrees at 8 knots, visibility 10 miles, scattered clouds at 4,700 feet above ground level, temperature 35 degrees C, dew point 27 degrees C; altimeter 29.71 inches of mercury. The numbers correlated to an approximate pressure altitude of 652 feet and a density altitude of 3,035 feet.

WRECKAGE AND IMPACT INFORMATION

The airplane impacted the ground with the left wingtip approximately 780 feet from the threshold for runway 4 and came to rest about 730 feet from the runway threshold. The airplane was examined at the site and all major components were accounted for on scene. A detailed field examination of the airframe and powerplant revealed no preimpact anomalies of the airplane.

The initial impact point was approximately 30 feet aft of the trailing edge of the rudder. The initial impact crater consisted of blue and white composite pieces and a wingtip light holder that was absent a lens or bulb.

The left wing was detached from the airframe and exhibited impact and crush damage to the outboard two-thirds of the wing; the inboard 4 feet exhibited thermal damage. The wing’s crush damage was in the aft direction and very slightly in the positive direction. The counter weight remained attached. The pitot tube remained attached as well as the stall sensor switch, which was checked for continuity utilizing an ammeter and was confirmed to be operational. The wing flap was thermally damaged and the mechanical flap tube was cut by local authorities; an accurate flap position could not be determined. The aileron was impact damaged; however, continuity was confirmed from the aileron bellcrank to the cable sever point that was created by the local authorities. Continuity was also confirmed from the sever point to the cockpit control column base attach point. The wing struts remained attached during the accident sequence; however, they were cut by local authorities during the recovery of the occupants. The fuel cap for the inboard 20 gallon fuel tank remained attached and in the secured position. Removal of the fuel cap revealed an odor similar to aviation fuel and a small amount of fluid that was blue in color was observed within the tank. Although the tank was breached, the fluid amount appeared to be approximately 1 gallon. The gascolator, located in the left wing, remained attached to the wing spar; it was removed and fluid consistent in smell and color to 100 low lead aviation fuel was present. The fuel screen was removed and appeared normal in condition and had no evidence of any foreign objects or debris. The outboard 15 gallon fuel tank was impacted-separated and was located next to the fuselage. The fuel tank exhibited extensive thermal and crush damage and was devoid of fluid.

The right wing had extensive thermal damage. The outboard fuel tank was present and had extensive amounts of thermal and crush damage, and the inboard fuel tank could not be identified due to the thermal damage to the wing. The counterweight exhibited thermal damage but remained attached. Aileron control cable continuity was confirmed from the aileron bellcrank to a torsional-overload fracture and from the fracture point to the base of the control column. The flaps exhibited extensive thermal damage and an accurate pre-impact flap position could not be determined.

The empennage and fuselage exhibited extensive thermal damage. The outboard 15 inches of the left side of the elevator were bent forward and in the negative direction and the entire rudder and elevator were destroyed by thermal damage. The rudder trim tab remained attached and appeared to be set slightly nose right. The elevator trim tab remained attached and indicated a slight nose down attitude. Control continuity was confirmed from the associated control surface to a cable cut performed by the local authorities and from that cut to the area immediately adjacent to the rudder pedals and the base of the control column.

The left amphibious float exhibited thermal and impact damage. The forward cross tube remained attached and had dirt and grass embedded into the fractured end of the tube. The aft cross tube was impact-separated. The left float was located to the right side of the right float and was facing in the opposite direction compared to the rest of the airplane. The forward 6 feet had impact and crush damage. Some of the damage was consistent with the float coming in contact with the right float and causing the left float to pivot around the right float during the accident sequence. The floats forward strut remained attached to the float but was impact-separated from the fuselage. The aft strut was impact-separated and found in close proximity to the float. The aft landing gear remained attached and in the down position; however, the forward landing gear was impact separated and located adjacent to the separated propeller blade, which was located 4 feet aft of the rudder. The water rudder remained attached and in the extended position; however, the cables to the rudder from cockpit were separated, allowing the rudder to be in the extended position. Examination of the float did not reveal any water or fluid inside and the float was absent of any signs of hydraulic deformation.

The right amphibious float indicated the landing gear was extended; however, the aft gear was thermally damaged, and the forward gear was bent in the aft direction but remained attached. The forward 6 feet of the float was bent toward the right and exhibited crush and impact damage marks. Some of the impact marks aligned with similar damage to the left amphibious float, indicating contact with each other. The float remained attached to the fuselage structure at the aft attachment point by the aft tube and the forward tube was cut by local authorities; however, the cross tubes were impact-separated. There was thermal damage to the aft one-half of the float. The water rudder remained attached and in the extended position; however, the cables to the rudder from the cockpit were separated allowing the rudder to be in the extended position. Examination of the float did not reveal any water or fluid inside and the float was absent of any signs of hydraulic deformation.

The engine exhibited extensive thermal damage. Cylinder No. 2 valve cover and cylinder body were thermally damaged. The top and bottom spark plugs were removed and appeared dark in color with normal wear. The bottom spark plug to cylinder No. 6 was found attached to, and hanging from, the plug wire. Other than extensive thermal damage, there were no other noted failures of the plug or cylinder plug hole. The engine oil pan was thermally damaged and absent, exposing the crankshaft and counterweights. The valve covers were removed and cylinder No. 1 had oil present. The engine was rotated approximately 60 degrees utilizing the propeller flange and continuity was confirmed through the rear accessory drive. The crankshaft was observed rotating through the absent oil pan and some of the lifters were observed moving. The oil dipstick remained attached, thermally damaged, and void of oil. The propeller governor was removed and rotated smoothly and had oil present. The alternator remained attached and the starter was separated due to thermal damage. The throttle quadrant was thermally damaged and an accurate position of the throttle and mixture control could not be determined.

The propeller assembly consisted of three propeller blades. Two propeller blades remained attached to the propeller hub; they were thermally damaged, exhibited S-bending, and tip curling. The other propeller blade was located 4 feet aft of the rudder and was buried approximately 2 inches into the topsoil; it was relatively flat with slight S-bending, tip curling and exhibited chord-wise scrape marks.

MEDICAL AND PATHOLOGICAL INFORMATION

An autopsy was performed on the pilot on August 8, 2011, by the Office of the Chief Medical Examiner, in Manassas, Virginia. The autopsy findings included "blunt force trauma," and the report listed specific injuries. The cause of death was reported as two of the listed injuries.

Forensic toxicology was performed on specimens from the pilot by the FAA Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma. The toxicology report stated no ethanol or drugs were detected in the urine.

ADDITIONAL INFORMATION

The Maule M-7-235 Flight Manual, Section 2, "Limitations," indicated that the stall speed was between 45 and 53 knots, depending on the flap setting. Section 3.3, "Normal Flight Operations," stated in part, "Loss of altitude prior to recovery from a stall may be as much as 300 feet."

According to the FAA Publication FAA-H-8083-3A, Airplane Flying Handbook, Chapter 8, "Approaches and Landings," stated in part, "…it is recommended that the angle of bank not exceed a medium bank because the steeper the angle of bank, the higher the airspeed at which the airplane stalls…"

A certificated flight instructor performed some of the recent recorded training with the accident pilot in a different make and model than the accident aircraft. He indicated that, on two training flights, the accident pilot performed turns in the airport traffic pattern at 45 degrees of bank. On the most recent flight with the accident pilot, he did not properly recover the airplane after hearing the stall warning horn that sounded on short final, and had to be coached on how to recover from the impending stall.

A global positioning system (GPS) unit was downloaded at the National Transportation Safety Board Vehicle Recorders Laboratory and included data from the accident flight as well as 14 flights/power cycles within the 2 days of the accident. A review of the data for the last minute of recorded flight indicated that the airplane entered the left downwind at 758 feet and at 47 knots ground speed. On the downwind to base turn the airplane was at 692 feet and 44 knots ground speed. The last recorded data point was at 1349:37 and recorded 528 feet and 57 knots ground speed.

NTSB Probable Cause

The pilot's inadequate airspeed and excessive bank angle while maneuvering for landing, which resulted in an aerodynamic stall.